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TeV-Gamma Ray Astrophysics with the H.E.S.S. Telescopes. Thomas Lohse Humboldt University Berlin. NordForsk Network Meeting in Astroparticle Physics Bergen, November 10, 2006. Veritas. MAGIC. in construction. H.E.S.S. CANGAROO III. Cherenkov Telescopes (3 rd Generation).

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TeV-Gamma Ray Astrophysics with the H.E.S.S. Telescopes

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Tev gamma ray astrophysics with the h e s s telescopes

TeV-Gamma Ray Astrophysics

with the H.E.S.S. Telescopes

Thomas Lohse

Humboldt University Berlin

NordForsk Network Meeting in Astroparticle Physics

Bergen, November 10, 2006


Tev gamma ray astrophysics with the h e s s telescopes

Veritas

MAGIC

in construction

H.E.S.S.

CANGAROO III

Cherenkov Telescopes (3rd Generation)


Tev gamma ray astrophysics with the h e s s telescopes

TeV -Astronomy: The Physics Shopping List

  • Cosmic ray origin and acceleration

  • Supernova remnants

  • Starburst galaxies

  • Clusters of galaxies

  • Unidentified galactic sources/surveys

  • Astrophysics of compact objects

  • AGNs

  • Micro-Quasars & Stellar-mass black holes

  • Pulsars

  • Gamma ray bursts

  • Cosmology

  • Diffuse extragalactic radiation fields via cutoff in AGN spectra

  • Astroparticle physics

  • Neutralino annihilation in DM halos


Tev gamma ray astrophysics with the h e s s telescopes

H.E.S.S.

High Energy Stereoscopic System

MPI für Kernphysik, Heidelberg

Humboldt-Universität zu Berlin

Ruhr-Universität Bochum

Universität Erlangen-Nürnberg

Universität Hamburg

Landessternwarte Heidelberg

Universität Tübingen

Ecole Polytechnique, Palaiseau

APC, Paris

Universite Paris VI-VII

CEA Saclay

CESR Toulouse

GAM Montpellier

LAOG Grenoble

Paris Observatory

LAPP Annecy

Durham University

Dublin Inst. for Advanced Studies

NCAC Warsaw

Astronomical Observatory Cracow

Charles University Prag

Yerewan Physics Institute

North-West University, Potchefstroom

University of Namibia, Windhoek


H e s s site

Farm Göllschau, Khomas Hochland, 100 km from Windhoek

23o16’ S, 16o30’ E, 1800 m asl

H.E.S.S. Site

  • Clear sky

  • Galactic centre culminates in zenith

  • Mild climate

  • Easy access

  • Good local support

    (UNAM etc.)


H e s s phase i

H.E.S.S. Phase I

4 telescopes operational since December 2003

Energy threshold (for spectroscopy): 100 GeV

Single shower resolution: 0.1

Pointing accuracy: ≲ 20

Energy resolution:  20%

June 2002

September 2003

February 2003

December 2003


Tev gamma ray astrophysics with the h e s s telescopes

960 pixel PMT camera

Pixel size: 0.16°

On-board electronics

Weight: 900 kg

13m dish, mirror area 107 m2

382 spherical mirrors, f =15m

Point spread 0.03°-0.06°


Tev gamma ray astrophysics with the h e s s telescopes

Selected Results from H.E.S.S.

  • Particle Acceleration in Supernovae

  • The Galactic Centre

  • The Gamma Ray Horizon

  • Gamma Rays from a Super-Massive Black Hole

  • Gamma Rays from a Micro-Quasar


Tev gamma ray astrophysics with the h e s s telescopes

Supernovae


Tev gamma ray astrophysics with the h e s s telescopes

But what about hadrons (protons and nuclei)?

Pulsar Wind Nebula:

Electron wind from centralpulsar heats the cloud

Synchrotron radiation

The Standard Candle for TeV -Astronomy

Crab Supernova 1054 a.D. d = 2 kpc

optical

1 lightyear


Tev gamma ray astrophysics with the h e s s telescopes

Cassiopaeia A Supernova 1658 a.D. d = 2,8 kpc

X ray picture

  • “Shell Type” SNR:

  • no electron wind from pulsar

  • gamma signal from shell regions not totally drowned in that of electron wind

  • good source class to observe hadron acceleration


Tev gamma ray astrophysics with the h e s s telescopes

RX J1713.73946

RX J1713.73946

E 210 GeV

H.E.S.S. 2004

E  210 GeV

H.E.S.S. 2004

resolution

resolution

First Resolved Supernova Shells in -Rays

RX J0852.04622

H.E.S.S. 2005

E 500 GeV

Strong correlation with X-ray intensities

  • SN-Shells are accelerating particles up to at least 200TeV!

  • But are these particles protons/nuclei or electrons?


Tev gamma ray astrophysics with the h e s s telescopes

Matter Density

B

Ee

Stars

Dust

Cosmic

Proton

Accelerators

Cosmic

Electron

Accelerators

CMB

B

Ee

Inverse Compton

Synchrotron Radiation

0

Synchrotron Radiation of Secondary Electrons

Electron or Hadron Accelerator?

radio infrared visible light X-rays VHE -rays

E2 dN/dE

log(E)


Electron accelerator fits for rx j1713 7 3946

B7,9,11G

2.0,2.25,2.5

EGRET

2.0

B10G

Electron accelerator fits for RX J1713.73946:

  • Continuous electron injection over 1000 years

  • Injection spectrum: power law with cutoff

H.E.S.S.

  • large  & injection rate  bremsstrahlung important

  • needs tuning at low E

  • IC peak not well described

  • B-field low for SNR shell


Tev gamma ray astrophysics with the h e s s telescopes

RX J1713.73946

H.E.S.S.

Proton accelerator fit:

  • Continuous proton injection over 1000 years

  • Injection spectrum: power law, index 2

  • Different cutoff shapes & diffusion parameters


Tev gamma ray astrophysics with the h e s s telescopes

Galactic Centre

HESS J1745290

HESS J1632478

HESS J1825137

RX J1713.73946

HESS J1616508

HESS J1837069

HESS J1804216

HESS J1745290

HESS J1708410

HESS J1834087

HESS J1813178

HESS J1614518

G0.90.1

HESS J1747281

HESS J1713381

HESS J1634472

HESS J1640465

HESS J1702420

Galactic Centre


Tev gamma ray astrophysics with the h e s s telescopes

Possible Interpretation: Dark Matter annihilation?

Crab

GC

MAGIC

H.E.S.S.

  • no visible cut-off  rather large mass

  • measured flux  large cross-section and/or DM density

20 TeV Neutralino

20 TeV Kaluza Klein particle

… unlikely !


Tev gamma ray astrophysics with the h e s s telescopes

Galactic Centre Neighbourhood

SNR G0.90.1

HESS J1747281

Galactic Centre

HESS J1745290

EGRET GeV--sources

~150 pc


Tev gamma ray astrophysics with the h e s s telescopes

HESS J1745290

Galactic Centre Neighbourhood

...point sources subtracted

  • first resolved detection of diffuse TeV--radiation

  • cosmic rays (hadrons) interacting with molecular clouds

molecular clouds density profiles

~150 pc


Tev gamma ray astrophysics with the h e s s telescopes

diffuse

radiation

expected flux for CR spectrum observed on earth

Cosmic Ray Spectrum at the GC...

is very different from the one at earth

Cosmic rays are much harder and have 3 larger density around the GC

Possible reason:

Close-by source population

Possibly single SN-explosion


Tev gamma ray astrophysics with the h e s s telescopes

The Gamma Ray Horizon


Tev gamma ray astrophysics with the h e s s telescopes

Blazars

  • General Active Galactic Nuclei (AGN):

  • Supermassive black holes, M  109 M

  • accretion disk and relativistic jets

  • Blazar-Typ: Jet points towards the earth

  • Doppler-boost  TeV -radiation


Tev gamma ray astrophysics with the h e s s telescopes

e+

e-

dN/dE

dN/dE

E

E

Absorption in (infrared) extragalactic background light (EBL)

(TeV) + (EBL)  e+e-

Measurement of EBL ( Cosmology)

Physics of compact objects,

acceleration/absorption in jets,…


Cut off energy and ray horizon

Cut-off Energy and -Ray Horizon

PG 1553113


Tev gamma ray astrophysics with the h e s s telescopes

EBL

Hardest plausible

source spectrum

 = 1.5

EBL Unfolding of Measured Spectra

Too much

EBL

1 ES 1101

 = 2.9±0.2

H 2356 (x0.1)

 = 3.1±0.2

H 2356 (x 0.1)

G = 3.1±0.2

Preliminary


Tev gamma ray astrophysics with the h e s s telescopes

excluded by H.E.S.S.

Assumed shape for rescaling

H.E.S.S. upper bound

fromspectral shapes of

1ES 1101-232 (z = 0.186)

H 2356-309 (z = 0.165)

New Upper Bound on EBL Density

EBL density seems 2 smaller than expected! Little room for EBL sources other than galaxies (early stars…)

Direct IRTS

Measurements

Upper Limits

Lower Limits

(Galaxy Counts)


Tev gamma ray astrophysics with the h e s s telescopes

M87

Gamma Rays from the Rim of a Super-Massive Black Hole


Tev gamma ray astrophysics with the h e s s telescopes

Radio

VHE -Rays

99.9% c.l. extension upper limit

host galaxy (optical)

  • Radio Galaxy, Virgo Cluster, d16Mpc

  • Central 3109M⊙ Black Hole, RS1015cm

  • Relativistic Plasma Jet at 30  Blazar

M87

Is there a better way to constrain the source size?


Tev gamma ray astrophysics with the h e s s telescopes

relativisticDoppler factor

v  c

reasonable: 150

time smearing: R/c

source variability: t* ≳ R/c

shortest observable variability: t ≳R/c

 upper limit on source size: R≲ct

Yes, there sometimes is: Source variability!

R

source


Tev gamma ray astrophysics with the h e s s telescopes

Doubling times of 2 days observed during 2005 high state of M87

Radio

optical

X-ray

knots (jet)

nucleus

  • Knots in jet are excluded as sources

  • High energy particles created close to black hole horizon


Tev gamma ray astrophysics with the h e s s telescopes

Gamma Rays

from a

Micro-Quasar


Tev gamma ray astrophysics with the h e s s telescopes

superior conjunction

0.058

Periastron

0

Apastron

0.5

inferior conjunction

0.716

observer

LS 5039

  • Massive star M20M⊙

  • compact object: 1.5-5M⊙ neutron star or black hole?

  • Orbital Period 3.9 days

  • Eccentric orbitbinary separation 2-4.5R*


Tev gamma ray astrophysics with the h e s s telescopes

superior conjunction

0.058

Periastron

0

Apastron

0.5

inferior conjunction

0.716

observer

Paredes et al. 2000

LS 5039

  • Faint X-ray emissionslightly variable

  • Extended pc-scale radio emission possibly from jets (v0,2 c)


Tev gamma ray astrophysics with the h e s s telescopes

0.058

0

0.5

0.716

observer

VHE -Ray Lightcurve folded with orbital period

H.E.S.S.

Modulation  absorption in radiation field

 central emission (1au)


Vhe spectral modulation

VHE Spectral Modulation

  • modulation strength strongly energy dependent

  • not explainable by pure absorption effects

  • complicated interplay between production & absorption mechanisms

The central engine starts to reveal its physics


Tev gamma ray astrophysics with the h e s s telescopes

The Future: H.E.S.S. Phase II

  • Large telescope under construction

  • Improve sensitivity: 4 small  1 largebetter than8 small

  • Reduce threshold to O(20 GeV)


Summary

Summary

  • Very successful initial years of H.E.S.S. Phase I

  • Many new sources & several fundamental discoveries

  • The VHE -ray sky is well populated and complex

  • Expect “bright” future


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